<!DOCTYPE html>
<html>
<head>
<style>
body {
  margin-top:100px;
  opacity:0.5;
}

.container {
  width: 120px;
  height: 120px;
  perspective: 100px;
}

.bottom {
  width: 120px;
  height: 120px;
  position: absolute;
  background-color: rgba(255,0,255,1);
  transform: translateZ(60px) translateY(120px) rotateX(-90deg);
  transform-origin: left top;
}
</style>
</head>
<body>
<div class="container">
  <div class="bottom"></div>
</div>
</body>
</html>
